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CONCERNING SOILS, GERMS 
AND WORMS. 



BY 
Dr. PERSIFOR FRAZER. 



Reprinted from the Journal of the Franklin Institute, 
April, 1904. 




PHILADELPHIA 




1 



1904. 



Reprinted from the Journal of the Franklin Institute, April, 1904. 

CHEMICAL SECTION. 

Stated Meeting, held March ij, iqoj. 

Concerning Soils, Germs and Worms.* 



By Dr. Persifor Frazer. 



In Part III of the Report of the Geology of New Jersey, 
of 1868, under the head of "Economic Geology," the 
Director, Prof. Geo. H. Cook, says : " In the detailed geology 
and under the proper heads, will be found chemical analyses 
of gneiss, limestone, slate, shale, trap rock, clay, green sand, 
etc. The soils are mostly derived from these ; sometimes 
from one, and sometimes from a mixture of two or more of 
them. And this geological classification is the best that 
can be made. A more common classification is into sandy, 
loamy and clayey soils. The latter, however, is not capable 
of general use. The meaning of the terms always depends 
on the experience of the person who uses them. What in one 
part of the State is called a clayey soil, in another part is 
called a loamy soil, and in still other places it would be 
called sandy," etc., etc. This statement will furnish an 
appropriate introduction to the observations on soils which 
are here proposed, since it shows how vague is the average 
conception of the character of that storehouse whence we 
draw our life. But the farmer's division into sandy, loamy, 
and clayey is not more crude than was that of the aver- 
age geologist. To him soils were but the comminuted 
rocks of the earth's crust mixed with more or less adven- 
titious organic matter, and moistened by the rain, the dew, 
and the capillary flow of the ground waters. Professor 
Cook, as he says, " to show how light or sandy a soil will 
produce vegetation," instances in the same chapter the fol- 
lowing analysis of beach sand from Old Beach, Atlantic City : 

* Substance of a lecture delivered before the Pennsylvania Horticultural 
Society, Tuesday, April 18, 1899, by Dr - Persifor Frazer, Professor of Horti- 
cultural Chemistry, Penna. Hort. Soc. Subsequently revised to January I, 
1904, and in part rewritten. 



2 



Silicic acid and quartz 95'44 

Alumina 1 JTO 

Peroxide of iron i 

Lime 0*45 

Magnesia o'22 

Water 0*30 

Total 99'4i 

In the report of the geological survey of New Jersey for 
1879, glass sand and sandy clays are noted as producing 
oak-land and pine-land soils. 

How very different is the idea of a soil in the minds of 
the agricultural chemists of the present day may be judged 
by Wiley's definition (" Principles and Practice of Agricul- 
tural Analysis." Chemical Pub. Co., Easton, Pa., 1894): 
" The term soil, in its broadest sense, is used to designate 
that portion of the surface of the earth which has resulted 
from the disintegration of rocks and the decay of plants 
and animals, and which is suited, under proper conditions 
of moisture and temperature, to the growth of plants. It 
consists, therefore, chiefly of mineral substances, together 
with some products of organic life, and of certain living 
organisms, whose activity may influence vegetable growth 
either favorably or otherwise. The soil holds various quan- 
tities of gaseous matter and of water, which are important 
factors in its functions." Yet it is possible to make plants 
grow without the intervention of any soil in the sense of 
the last definition (Storer, "Agriculture in Some of Its Rela- 
tions with Chemistry " ); for not only does the mistletoe grow 
in the air, but hyacinths, cuttings of rose bushes, trade scantia, 
and Indian corn, or almost any of the ordinary grains, may 
be made to grow and bear seeds in glasses of water, provided 
the latter contain some ash-producing material and some 
nitrates, which are ordinarily derived from the soil. How- 
ever small the amount, some potash, lime, magnesia, iron, 
phosphoric, sulphuric and nitric acid (or, in the place of the 
last, ammonia) must be present in order to develop the 
plants of the higher orders (id. I). 

Soil is necessary as a prop for the plant in nature, as well 
as a sponge from which to extract the food which is to sus- 



tain it ; and for certain plants, such as tubers, the light, 
easily-displaced covering of pure silica sand, when once well 
manured, produces more perfectly formed plants than the 
less yielding natural mold. 

The passage of water and its saline constituents through 
a plant, and the evaporation of the former (or, more prop- 
erly, its exhalation, since the process is connected with the 
life of the plant and may take place, unlike ordinary evapo- 
ration, when the surrounding atmosphere is saturated with 
moisture), results in an enormous circulation, estimated by 
Watson at 30 hogsheads of water on every acre of grass land 
per day. About 300 parts, by weight, of water pass through 
a plant to one part fixed and assimilated in its tissues. 

Ordinary soils contain large quantities of nitrogen ; in 
fact, by a series of experiments on Scotch soils and manures 
made by Anderson, the average proportion of organic matter 
in the soils was 7*02, and of nitrogen in this organic matter 
0*206 ; or a relative proportion of nitrogen to organic matter 
in the natural soil of somewhere near 1:35; whereas in the 
manures applied to the eight farms from which these various 
soils were taken, the average proportion of organic matter 
was i3'94, and of nitrogen 0'382. The proportion of the 
nitrogen to the organic matter in the manures was as 
1 : 36*49. Consequently, the relative proportion of this 
invaluable plant food element was higher in the natural soil 
than in the manure laid on to enrich it.* Professor Storer con- 

*It is interesting in this connection to note the " fertilizing ingredients" 
and their cost, enumerated by Mr. MacFarlane in his admirable report on 
"Fertilizers." The quantity of each ingredient in a given fertiliztr must, 
according to Dominion law, be stated by the dealer. (Published by the 
Inland Revenue Department of Canada, Bulletin 86, Ottawa, 1903. ) 
Nitrogen in salts of ammonia or nitrates as well as in com- 
pound fertilizers $0 13 

Organic nitrogen in ground bone, fish, blood or tankage ... 12 

Phosphoric acid — soluble in water 6 

" " " 1 percent, citric acid 5^ 

" insoluble in Thomas' phosphate powder . . 3^ 
ground rock phosphate and 

fertilizers generally 1% 

Potash contained in wood ashes 6 

" from high-grade salts 5% 



siders the utilization of these natural and almost inexhausti- 
ble supplies of nitrogen among the most important of the 
problems of to-day, and adds that from remote time the 
improvement of the soil-nitrogen has been deemed, by wise 
cultivators, more advantageous than employing fertilizers, 
or keeping additional cattle to produce more manure. These 
stores of nitrogen are found in arable loam, leaf mold, peat, 
swamp and marsh mud, etc., and here is where an agent 
often neglected renders valuable service, as will be seen 
further on. 

The effect of " symbiosis," as Storer calls it, or blended 
life of various kinds, is well illustrated by the little knobs 
and warts on the roots of clover and leguminous plants. 
The most generally received explanation of this phenome- 
non now is that bacteria enter the roots from the soil, and 
form colonies within the roots, thus giving rise, by the 
mutual growth of bacteria and plant-cells, to those excres- 
cences. The lower organisms thrive on the juices of the 
plant, and in turn render some service in supplying these 
roots with nitrogen. Hellriegel has shown that nitrogen 
from the air is stored up for the benefit of such plants, even 
when the latter are grown in sand free from organic or 
nitrogenous matter. Nodules form upon the roots at the 
time that nitrogen is being taken from the air; but material 
akin to the ash-residue of the normal plant must be strewn 
with the sand. When growth ceased, in such experiments, 
occasionally germs from the air fell upon the sand and 
started the growth anew ; but on supplying water, which 
had been in contact with garden loam and was charged with 
bacteria, the full and healthy growth was recommenced, 
and the plants assumed their normal dark-green color. The 
plants feed upon the substance of the bacteria after the 
latter have died. 

These plants, which get nitrogen from the bacteria, charge 
the soil with nitrogen to the benefit of succeeding crops of 
other plants ; and this is the modern explanation of the 
utility of rotation in crops, which has been recognized prob- 
ably ever since husbandry began. A continuous succession 
of peas, for example, not only gives rise to nematode 



5 

worms, instead of bacteria nodules on the pea roots, but 
these worms are transferred to the next crop which is put 
in, and impair or ruin it. 

Great lichens, such as reindeer moss, or Iceland moss, 
grow freely on bare rocks and sterile soils. Fungoid growths 
are noticed, even covering in a few days surfaces of iron. 
These fungi produce large quantities of nitrogenous organic 
matter. 

Berthelot showed that certain nitro-organisms living in 
soil feed on the nitrogen of the air, and produce nitrogen 
compounds, at first insoluble in water, but later converted 
into soluble nitrates, to the amount of 75 to 100 pounds per 
acre per annum. 

But the fixation of nitrogen by nitro-organisms in the 
soil is less important than that by bacteria on the roots of 
leguminous plants. 

The general conclusions as to nitrogen and micro- 
organisms in their relations to plants, reached through the 
work of Atwater, Wagner, Heiden, Hellriegel and Wood 
(of the Storrs Agricultural School in Connecticut), may be 
thus summarized : 

Pease, alfalfa, serradella, lupine, probably clover, and in 
general all leguminous plants acquire large quantities of 
nitrogen from the free nitrogen of the air during growth. 

It is clear that there is a connection between the root 
tubercles and this acquisition of nitrogen, but what the con- 
nection is remains to be discovered. 

Cereals which have been experimented with have not 
shown this power of taking nitrogen, nor had they such 
tubercles as are found on the roots of legumes. 

In the experiments undertaken soil infusions did not seem 
necessary for the production of root tubercles. It is con- 
sidered probable that the micro-organisms or spores were 
floating in the air and thence found their way to the pots in 
which the plants were growing. 

As a rule in the experiments, the greater the abundance 
of root tubercles, the larger and more vigorous the plants, 
and the greater the gain of nitrogen from the air. 

Where loss of nitrogen occurred there were no root 
tubercles. It was largest with oat plants and largest where 



they had most nitrogen at their disposal in the form of 
nitrates. The gain of nitrogen in legumes helps explain 
why they act as renovating crops, and the loss in the case 
of oats suggests why they should be an exhausting crop. 

(MacFarlane, Bulletin 86. Canadian Report I. R. D.) 

On barren ledges of rocks the frost and other causes 
produce disintegration, and the spores of fungi resting on 
this talus produce nitrogenous matters from the air. The 
soil is then ready for the next step, which is the making of 
mold. 

Humus, according to Storer, is the organic portion of all 
the earth-like products which results from the decay of 
vegetable or animal matters. In temperate climates the 
tender parts of vegetable matter are converted by the oxy- 
gen present into carbon dioxide and water (through micro- 
organisms chiefly), and the residue is humus, which resists 
further decay. 

The acids of various constitution, together known as 
humic acid, though not very soluble in water, are chemic- 
ally active. 

Agricultural plants, in general, cannot feed directly upon 
humus, but, through the micro-organisms which feed on it, 
are supplied with nitrogen. 

Three ferments in all are needed : one to set free am- 
monia; one to produce nitrites from it; and one to produce 
nitrates from nitrites. Nitrification is most active in hot 
summer weather. No nitrates are produced by putrefying 
processes. On the contrary, nitrates, if present, are con- 
verted into ammonia. 

In an experiment made by Leone with nitrates and hen- 
dung in loam, placed in a box so that air could freely pass 
between the particles, first nitrates were partially reduced 
to nitrites. In a fortnight both nitrates and nitrites disap- 
peared, and only ammonia was detected. In little over a 
month, nitrates again began to appear, and in three months 
there were only nitrates. Lorgna defines nitrification as the 
last term of putrefaction. 

The above experiment shows how easily an injudicious 
treatment of a valuable manure may entirely destroy its 
efficiency. A few words on the value of farm manure 



and the best methods of securing, preserving, increasing its 
efficacy, and applying it, seem here appropriate. Hell- 
riegel, in 1897, proposed a simple plan easily applicable 
everywhere and every year, by means of which a practical 
agriculturist may see differences between adjacent crops 
treated differently, and thus decide what should be the 
substance applied to the soil to insure the best harvest. It 
is to pass over a few square rods of the field, at various 
places properly selected, without applying dung or fertilizer. 
In accordance with this principle other plots of like dimen- 
sions may be treated respectively with lime, marl, dung, or 
fertilizers. The heights and densities of the resulting crops, 
the fulness of the ears and the development of the grains, 
etc., may easily be compared, and a correct conclusion 
drawn as to what is best for that particular soil. 

J. Koenig, in his prize essay, " How Can the Farmer Pre- 
serve and Increase the Stock of Nitrogen on His Property?" 
(Berlin, 1887), gives the results of his investigations and 
experience as follows : 

(1) In the decomposition of nitrogenous substances of 
every nature a loss of free nitrogen, more or less consider- 
able, takes place. 

(2) This loss is the greater the more the atmosphere has 
access to the decomposing mass. 

(3) Too much moisture is as hurtful as too little. Stable 
manure requires such a degree of humidity as permits its 
components to lie close together. 

(4) The addition of substances which fix ammonia (such 
as gypsum, kainite, and kieserite) prevents or reduces the loss 
of nitrogen. These substances are, however, of little or no value 
if care be not taken at the same time to prevent as much as possi- 
ble the access of air. 

In storing stable manure, it should be kept in a water- 
tight receptacle, roofed in, and it is desirable that it be 
trodden down by the farm animals. It is perfectly clear 
that the use of gypsum or ordinary ground land plaster pre- 
vents any loss of nitrogen in the stable, and, according to 
Holdefieiss, Vogel, and others, the same substance, or gyp- 
sum produced in the manufacture of the acid phosphate, 
prevents the loss of ammonia from the liquid part of the 



manure. Another suggestion by Dr. C. A. Goessmann, 
Chemist for the Massachusetts Agricultural College (Bulle- 
tin 45, March, 1897), is that there should be added to the 
manurial refuse materials of the farm such single manurial 
substances as will enrich the former in the directions desir- 
able for any particular crop. 

(Canadian Inland Revenue Department Bulletin, No. 86, 
before cited.) 

The substance of the following notes on bacteria is 
taken from an interesting lecture entitled " The Analysis 
of Water, Chemical, Microscopical and Bacteriological," 
before the Lowell Institute, Boston, December 5, 1889, 
by Dr. Thomas M. Drown, then Professor of Analytical 
Chemistry in the Massachusetts Institute of Technology, 
now President of Lehigh University, Pennsylvania. In 
speaking of the bacteria found in the sanitary analysis of 
potable waters, he says : The bacteria belong to the lowest 
form of life ; a simple cell, with wall and contents, capable 
of self-nourishment and reproduction. Until within a few 
years their presence was unknown and unsuspected, so 
minute are they, and yet their importance in the economy 
of nature is such that higher life would come to an end if 
their activities were to cease. It is unfortunate that these 
ever-present, humble, useful organisms should be associated 
in our minds mainly with evil purpose and effect. True, 
there are malignant bacteria, to which we cannot assign 
any beneficial role in nature ; but so there are poisonous 
fruits. 

The bacteria, or germs, as they are also called, have many 
shapes ; the ball or egg-like forms include the genera micro- 
coccus and streptococcus; the rod-like forms, the genus 
bacillus ; and spiral forms, the genus spirillum. A special 
form of bacteria we have all become familiar with in name 
— the cholera germ, called by Koch the comma bacillus. 

The function of the green plant is to make organic ma- 
terial out of the inorganic. Trees, grass, and vegetables 
live entirely on the carbonic acid of the air and the water 
and mineral matters in the soil. Animals cannot do this, 
but require either vegetable or animal food. In utilizing 
this food, the animals do not reconvert it all into mineral 



matter again. The nitrogen in the proteid, or albuminoid 
matter which they consume, is not excreted in the oxidized 
form of nitrates, but as urea, a compound related to am- 
monia. Then the bacteria step in, find food for their sup- 
port in the waste which has no more value for animal life, 
and complete its conversion into mineral matter that it may 
again serve as food for plants. 

The method employed to determine the numbers of bac- 
teria is based on the principle that by stimulating their 
growth and making them increase enormously within a 
small space, in which they cannot move, the aggregations of 
the newly developed bacteria will be so large that they can 
be seen by the naked eye. This ingenious suggestion was 
carried out by the famous bacteriologist, Koch, in this way: 
A small quantity, usually i cubic centimeter, of the water 
(that is, about one-fifth of a teaspoonful) is mixed thor- 
oughly with, say, ten times its amount of a sterilized solu- 
tion of gelatine, which contains extract of beef, peptone, 
etc., to make it highly nutrient, and the mixture is poured, 
while warm, upon a glass plate, so that it forms a thin layer 
when solidified. This is set aside for a few days in a warm 
room under a cover, and protected from the germs in the 
air. If bacteria are present in the water they will grow 
with great rapidity under these conditions, each bacterium 
forming a colony, as it is termed, of thousands or millions 
of bacteria. Then we can see and count them. It is as- 
sumed that each colony arose from a single bacterium in 
the water ; hence, by counting the number of colonies on a 
plate, we arrive at a determination of the number of bac- 
teria in the cubic centimeter of water used. 

The numbers of bacteria, as determined in this way in 
natural waters, vary greatly. A water taken directly from 
the ground, at a depth of six feet or more, should contain 
none. In good pond waters may be found anywhere from a 
few score to a few hundred. In polluted streams they may 
run up well into the thousands or hundred thousands, and 
in sewage they can be sometimes counted in the millions. 
Organic matter is composed of carbon, hydrogen, oxygen, 
and nitrogen ; at least, for our purpose it will suffice if we 
so consider it. It is only the nitrogenous organic matters 



10 



which undergo those kinds of changes which we include 
under putrefaction, and which we regard of importance 
from a sanitary standpoint. Familiar examples are milk 
and meat, which, when exposed to the air, become offensive, 
but starch and sugar (which contain no nitrogen) do not. 

The nitrogen which we find on analysis from undecom- 
posed animal and vegetable matter, say fresh albumen, we 
call " organic nitrogen," by which we mean that the nitrogen 
is still in its original combination before change or decay 
has set in. Leaving out of consideration that present in 
rain-water, we may say that ammonia in water is distinctly 
characteristic of the first stage of the decomposition of 
organic matter. The term " organic nitrogen " has been 
used, but on the tables of analyses another is substituted, 
namely, "albuminoid ammonia." It is an unfortunate fact 
that the methods of determining organic nitrogen have been, 
until recently, very tedious and difficult, and not always 
reliable, so that chemists have resorted to another process, 
which gives only a part of the organic nitrogen in the form 
of ammonia. That is called albuminoid ammonia, because 
albumen, when subjected to this process, gives up its nitro- 
gen as ammonia. 

From the present methods of examining water the 
following facts are ascertained, (i) By means of the micro- 
scope, the kind of life existing in the water, from which 
conclusions are drawn as to the kind and quality of the 
food which supports this life. (2) By means of the gelatine 
plate cultures, the number of the bacteria in the water, 
from which conclusions are drawn as to the amount and 
kind of decay going on. (3) The purely chemical examination 
reveals directly the amount of organic matter, and the con- 
ditions in which it exists. These widely different methods 
are merely different points of view. It is one and the same 
thing throughout, namely, the life processes which are 
going on in the water ; for decay is but the manifestation 
of another form of life. 

If it is asked why study is centered here, the answer is, 
simply, that experience has taught that it is the organic 
matter which is the cause or accompaniment of disease ; it 
is during the decomposition of this organic matter, and in 



II 

some of the changes it undergoes in the process of decay, 
that danger lurks. This is the chemical expression of the 
causation of disease. The biological expression takes an- 
other form, namely, that the bacteria which cause changes 
in the organic matter cause also disease. The two expres- 
sions do not contradict each other, but go hand in hand. 
The chemical idea implied in both expressions is that the 
state of change is the state of danger. From an horticul- 
tural point of view, the state of change is the state of evo- 
lution. 

The vegetable mold which forms the rich top-soil of 
every agricultural country consists of a very uniformly fine 
mass of blackish color, usually only a few inches in thick- 
ness, though under exceptionally favorable circumstances it 
may reach a depth of nine or ten inches. Humus (of which 
there is a surprising lack of definition in the best works, but 
which is generally understood to be earth more or less 
charged with decaying organic matter) is well illustrated by 
beds of peat and so-called muck. The latter term, however, 
according to Storer, is misapplied, and should mean " well- 
rotted dung " (II, 78), though in this country, and especially 
in New England, it is synonymous with marsh mud. The 
vegetable mold, if not coincident with, at least contains 
the greater part of the humus in a given area, and it is in this 
that the germination of seeds and the growth of plants have 
their best development. 

The humus has been investigated by our countryman, 
Prof. A. A. Julien (" On the Geological Action of Humus 
Acids." Pr. A. A. A. S., XXVIII, 1879, 311), by whose 
labors it is established that there are many acids of com- 
plicated constitution confounded under the name humic 
acid. All of them act energetically upon rocks, and per- 
form important functions in the preparation of the material 
with which they come into contact to facilitate plant 
growth, directly through the disintegration of leaves and 
animal tissue, and indirectly by furnishing food to the 
bacteria which are so indispensable to vegetable life. 

Charles Darwin, among the countless contributions of 
this greatest of naturalists to our understanding of nature, 
has observed (" The Formation of Vegetable Mold 



L.oFC 



12 



through the Action of Worms," etc.; Appleton, 1882) that 
the upper part of the intestines of earth worms generates 
the several humus acids which are produced by decaying 
vegetation. The calciferous glands lying below this tract 
produce a material which neutralizes the acids thus gener- 
ated, for the digestive fluid of worms will not act unless 
it be alkaline. These acids, he thinks, are generated during 
the digestive process, and are probably of nearly the same 
nature as the humus acids, so that the agency of worms in 
producing the material out of which that of plants is 
assimilated is evident. The action of worms is not con- 
fined to chemical changes, but extends in many widely dif- 
ferent directions, and, according to this accurate observer, 
is stupendous in its results. At the risk of repeating what 
is familiar to many of you, I will sketch briefly this action 
as epitomized in the work just cited. There are but few 
genera of earth worms distributed throughout the world. 
/Their mode of life is to burrow in the ground, which they 
do by eating a hole through the soil, and with the mouth 
filled, advancing the oesophagus, thus forcing the cheeks 
outward in all directions, crowding the soil aside, and en- 
larging the burrow. (" The Soil," etc., F. H. King, Pro- 
fessor Agricultural Physics in University of Wisconsin ; 
Macmillan & Co., 1896.) The material swallowed is passed 
through the calciferous glands lying midway in the oesopha- 
gus, where the acids are neutralized; through the crop and. 
gizzard, where the particles are triturated by the hard stones 
habitually retained there ; and into the intestine, where the 
pulp is again made acid ; whence, at the mouth of the bur- 
row, it is, voided in the form of castings or worm-dung in 
piles of greater or less size, and more or less retaining the 
mold of the intestines. The castings may be seen after a 
rain, especially in gardens and much-frequented walks. 
Earth worms work preferably at night, and lie close to the 
mouths of their burrows by day. The mouth of a worm is 
situated at the anterior end of the body, and by means of a 
lip the animals can grasp an object and draw themselves 
forward. Their intestine has a deep involution of its walls, 
by which additional absorbent surface is gained. They 
breathe through the skin. They are destitute of eyes, but 



13 

conscious of a bright light and sensitive to it in the anterior 
part of the body. They are less sensitive to radiant heat. 
They are very sensitive to touch or vibration, though not 
to sound. Their perception of odors is feeble, but enough 
to direct them to objects which they like to eat (cabbage 
leaves, onions, etc.). 

They are omnivorous, swallowing everything they can 
grasp, and extracting what nutriment the mass contains. 
Their preference is for half-decayed leaves, however, which 
they draw into their burrows partly for food and partly to 
close the entrances ; and to this circumstance is due much 
of the finest soil which they produce. 

They moisten the objects with a secreted alkaline fluid 
like pancreatic juice. The calciferous glands are probably 
fed with lime by the leaves in which this earth concentrates 
before they fall. This is excreted as carbonate of lime and 
aids the digestive process. The castings of worms are 
usually acid. Darwin concludes that they possess a low 
order of intelligence, in contradistinction to instinct. His 
experiments on this subject are very curious and instructive. 
With worms kept in a pot he observed the manner in which 
hundreds of objects of different shapes were drawn into 
their burrows, which are thus lined, he thinks, on account 
of the sensitiveness of the animals to cold, for the purpose 
of avoiding the contact of their bodies with cold, damp 
earth. The amount of work performed by worms is meas- 
ured by the rapidity with which objects laid on the ground 
become covered by their castings. There are instances of 
coal ashes, strewn over a large field, which were buried in 
this way 7 inches in eighteen years. The tesserae of pave- 
ments, ancient buildings, large stones (including some of 
the Stonehenge), ancient walls, etc., are found to be covered 
to a greater or less depth by the castings of earth worms, 
and independently of the action of other agencies. With 
this, of course, is to be reckoned the sinking of these objects 
through undermining by worms, and the subsequent colapse 
of the burrows. The soft mold removed from lower levels 
to the surface has passed repeatedly through the intestines 
of worms, and much of it has been finely triturated in their 
gizzards. Darwin estimates that, in each acre of earth 



14 

which is sufficiently damp and not too sandy, gravelly, or 
rocky for worms to inhabit, a weight of more than 10 tons 
of earth annually passes through their bodies and is brought 
to the surface. The result for a country of the size of Great 
Britain in, say, a million years, is 320 million million tons of 
earth in land which is cultivated and well fitted for these 
animals. It is probable, he thinks, that all of the finest 
vegetable mold which we see has passed again and again 
through the bodies of earth worms. 

There is a series, and perhaps a cycle, of changes from 
the partially cooled, still incandescent mass, and newly 
formed planet — the Earth* — to the well-cultivated hive of 
industry of to-day ; teeming with millions of workers prose- 
cuting countless industries, all of which depend upon the 
change of form of the materials which the earth furnishes, 
sometimes for the sake of these new forms, and sometimes 
for the sake of the forces which are incidentally generated ; 
but all of which are made possible by the life which the 
earth gives to the workers through the products of its soil. 

(1) There was the partially cooled, lava-like crust of the 
earth, glowing cherry-red, and surrounded by the heavy acid 
vapors and steam, wherein the volatilizable oxygen com- 
pounds of sulphur, phosphorus, nitrogen and the like, known 
as sulphuric, phosphoric, and nitric acids, pervaded and gave 



* A new view of the evolution of our planet eliminates incandescence and 
change from gas to liquid and from liquid to solid during the earth's history. 
[T. C. Chamberlm, Journal of Geology, vi, 609; vii, 545, 667, 752. H. Le Roy 
Fairchild, Bui. Geol. Soc. Am., vol. xv.] According to the modern substitute 
hypothesis the discrete matter derived from the hot nebular ring was cooled 
before it aggregated to form the earth. But even if this new view should ulti- 
mately displace the assumption that the earth was a hot fluid ball, which so 
many distinguished geologists have considered the necessary consequence of 
La Place's Nebular Hypothesis, it will not in any way affect the proposition of 
the interdependence of various forms of life herein stated. Neither the old 
nor the new hypothesis of the origin of the earth pretends to account for the 
advent of life, and its dawn is almost universally ascribed to a time when the 
surface of the planet was not greatly warmer than it is now. The only differ- 
ence is that the new theory gains the disposal of an immensely greater period 
of time during which this earliest life may have been evolved into the many 
forms existing to-day, and shakes itself clear of the fetters which Lord Kelvin 
and other physicists have put upon geological speculation. Professor Fair- 
child's plea is " Geology for the geologists ! " 



15 

their acid character to the dense, inky clouds of steam 
mingled with all other but the most unvolatilizable terres- 
trial elements. 

Finally, when additional cooling' had taken place, these 
acid vapors condensed and descended in torrents which ex- 
coriated the vitreous mass, and sent floods of highly satu- 
rated solutions into its natural depressions — the first com- 
mencement of a sea. The waters heretofore enveloping this 
planet in clouds like those of Mercury and Venus, descended 
in great mass and deluged the basaltic crust, cracking and 
comminuting it, and thus offering the acids more favorable 
opportunities to attack and dissolve its substance ; tearing 
away its salient prominences by crush of flood and gale ; 
spreading out the debris as a slime, mud, or sand in the 
natural channels ; and carrying the finest suspended particles 
into the sea. At last, the alkaline ingredients neutral- 
ized the acid waters, and the ocean contained only highly 
diluted neutral salts. 

The contraction of the nucleus produced new elevations 
and depressions, changing the old ones ; so that continu- 
ously the bottoms of the seas emerged and became dry land, 
and high ridges were depressed under the surface of the 
waters. Somewhere, either at this period or perhaps from 
the very beginning, appeared the force we call life because 
we cannot understand it ; and in all probability its lowest 
known form — perhaps some sort of bacterium. The deriva- 
tion from this simplest life-element of the lowest life-king- 
dom we recognize — that of plants — is not yet understood, 
but the advance accomplished, as always occurs in nature, 
the plants assisted, and were assisted by their predeces- 
sor in form, until still further progress was made ; each 
stepping-stone being used as a support to place the next, 
while the old were not destroyed ; just as a man flings blocks 
into a stream to cross dry-footed, and stands on the last he 
has planted to place the next. 

Then plant-growths imperceptibly changed in complexity 
and character to the second and highest life-kingdom — that 
of animals ; but so insensibly, and with so many interlock- 
ing characteristics among the beings which are found on the 
border line, that no definition has yet been found which can 



i6 

quite satisfactorily indicate the distinction between animal 
and plant, nor between plant and mineral, nor between vital 
and any other kind of force. 

Taking the sequence of events as they are, the infinite 
variety of plant and animal forms, from the minutest unit 
capable of being seen under the microscope to the gigantic 
California redwood, and the elephant, the lower forms and 
forces act as servants to the higher. The winds and frosts 
still tear new mineral matter apart, and the rivers and 
ocean grind, sift, and spread it into gently sloping prairies. 
The micro-organisms and the fungi invade this material, 
and, reaching to the atmosphere for the organic elements 
which it contains, translate this carbon and nitrogen into 
lichens, moss, herbs and humus. But with this' advance 
in the vegetable world an advance in the animal world 
has taken place pari passu, and, amongst other useful 
forms, the worms appear as husbandmen and workers of 
this crude mass into soil fit for the highest plants. Again 
and again this comminuted dust, with its bacteria, goes 
through the alimentarjr canal of the worm, and is spread 
over the surface, hard or soft, sterile or fertile alike, hid- 
ing the floor of our planet under the rich banquet which 
these humble creatures spread out for higher forms of the 
lower kingdom. 

Upon this spring the grasses and grains, the bushes and 
trees, which in turn send down their roots through the soil, 
and, saturating the unaltered crystalline rocks with their 
acids, prepare new material for the steps of preparation 
which have been described. On the higher forms of plant 
life the highest forms of animals live, the highest as 
well as the lowest representatives supplementing their 
simpler diet by feeding on each other. 

The processes are so various, the change of action so 
incessant, and in such endless rotation from purely physi- 
cal or chemical to vegetable and animal, that one is unable 
either to specify in what resides the high and the low in 
nature, or wherein the forces or the forms we recognize in 
the three kingdoms differ from each other fundamentally, 
in spite of the superficial differences which appear to our 
senses. 




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